Air jack



J. F. HARRBS AIR JACK May i5, i951 5 Sheets-Sheet l Filed Jun`e 9, 1947 FIG' FIG. 3.

R O T N E V m JOHN E HARRns ATTORNEYS May i5, E953 J. F. Hmm@ 2552?@55 A1B JACK Filed June 9, 1947 3 Sheejtsusheet 2 INVENTOR JOHN F. AMIS E?" 2am AT TOR NEWS May 315 395i J. F. HARRIS Zgf t AIR JACK Filed Jun@ 9, 1947 5 sheets-sheet s INVENTOR JOHN .E HMRI@ BY mw? ATTORNEYS Patented May 15, 1951 UNITED STATES PATENT OFFICE AIR JACK John F. Harris, Los Angeles, Calif., assigner to Leo F. Reisig, Los Angeles, Calif.

Application June 9, 1947, Serial No. 753,547

2 Claims. 1

The present invention relates to an air jack, and more particularly to an air actuated jack which is adapted to operate "under extremely low clearance and long reach conditions, as Weil as under all ordinary lifting conditions for which a jack customarily is employed.

Previous attempts have been made to develop air actuated jacks for use in lifting automobiles, but most of such jacks have been subject to limitations which made it difficult for them to compete with other types of jacks.

An object of the present invention is to make an improved and simplified air actuated jack.

Another object is to make an air actuated jack having a long reach and low clearance to facilitate inserting the jack into operating position beneath modern automobiles having long overhang and low road clearance.

Another object is to make an improved air actuated jack which will automatically lock itself in raised operated position to support a load thereon independently of its air actuating power.

Another object is to make an air actuated jack having an accessory lifting device adapted to grip, in supporting relation, portions of automobiles not adapted to receive usual jack lifting heads.

Another object is to make an air actuated jack readily adapted to lift automobiles from various lifting areas thereon.

Another object is to make a jack which will automatically draw a supporting base portion thereof into proper position beneath a load which is elevated by the lifting action of the jack.

Another object is to make an air actuated jack having lifting elements devised to provide minimum height throughout a maximum portion of its length, thereby to adapt the jack for inserting it beneath cars having minimum ground clearance.

Another object is to make an air actuated jack having improved lubricating facilities.

Another object is to make an air actuated jack having a lubricant reservoir mounted on a portion of the jack which is tilted during an operation of the jack, each tilting operation acting to dispense a portion of lubricant contained in the reservoir.

An embodiment of the invention for attaining those and other objects of the invention Will be set forth in the following description and in accompanying drawings, comprising three sheets. In the drawings:

Fig. 1 is a view in sidel elevation of an air jack embodying the present invention, in normal, unoperated condition;

Fig. 2 is a similar side elevational view of the jack shown in Fig. 1 as it would appear raised to operated condition, an automobile rear end portion being indicated in dotted lines as being supported thereby;

Fig. 3 is a fragmentary side elevational view showing the free end of the jack lifting arm as it would appear with a removable load engaging element mounted thereon;

Fig. 4 is a view similar to that of Fig. 3 with the load engaging element inverted from the position of Fig. 3 for engaging a different type of surface;

Fig. 5 is a plan view of the air jack shown in Fig. 1;

Fig. 6 is an enlarged fragmentary sectional view taken on the line 6 6 of Fig. 5;

Fig. 7 is a fragmentary sectional view taken on the line l-T of Fig. 6;

Fig. 8 is a further enlarged fragmentary sectional view taken on the line 8-8 of Fig. '7;

Fig. 9 is a sectional view taken on the line S-S of Fig. 1;

Fig. 10 is an enlarged sectional View taken on the line IU-I of Fig. 2;

Fig. 1l is a fragmentary sectional View taken on the line II-H of Fig. 1; and

Fig. 12 is an enlarged view in perspective of the load engaging element referred to in connection with the description of Figs. 3 and 4.

Referring to the drawings in detail, an illustrative embodiment of the invention comprises two major elements, namely`a supporting-base frame Eiland an elevating frame 2| pivotally connected, as at 22, to the rear end of the base frame. The base frame is provided with two rear supporting. wheels 23 and 24 mounted on stub shafts 25 and 25, respectively, secured as by Welding to the exterior sides of the base frame. A pair of front wheel support plates 28 and 29 are welded to the sides of the forward end of the base frame, and an axle 30 is mounted in openings in these plates to mount front supporting Wheels 3| and 32 thereon. A .pair of triangular side plates 33 and 34 are welded to the sides of the base frame, and a transverse rear plate 35 is Welded or otherwise secured across the upper ends of these side plates.

.A bent tubular handle 31 is secured to the upright frame provided by these triangular side may be mounted in sockets provided on the frame to receive the lower ends thereof, or it may be welded in place, as preferred.

The pivotal connection 22 between the base frame 29 and the elevating frame 2|, comprises a pair of stud shafts 38 and 39 mounted to prolect inwardly from the sides of the base frame I9. Bushings 4l) and 11| are secured to opposite sides of the rear end of the tilting frame 2|, and are pivotally mounted on the stud shafts 98 and 39 respectively.

An air cylinder t2 is provided with laterally extending support flanges 43 and 44 which are welded to the air cylinder. These support flanges rest on, and are bolted to, the sides of the elevating frame 2|. The structure of the air cylinder and its associated piston is best shown in Figs. 6, '7 and 8. The cylinder comprises a cylindrical shell portion having a rear head 45 secured thereto as by welding. A front head portion 5l is mounted removably in the cylinder, and may be held in place by cap screws 48.

A piston 49 comprises a head portion 59 with an, internally threaded socket 5| extending forwardly therefrom. A hollow piston rod 52, which also constitutes a lubricating oil reservoir, is threaded into this socket to have air tight connection therewith. The cylinder head portion 5i) is of less diameter than the cylinder, and a sealing ring 53, preferably of synthetic rubber, is mounted to encircle the piston head.

Inner and outer piston ring retaining plates 543 and are mounted on opposite sides of the piston head, the marginal portions of these members being adapted to grip the sealing ring between them. The piston ring retaining members Ell and 55 are drawn toward each other and into secured relation with the piston head 50, by a plurality of bolts 51 and 5B which are insertedr in registering holes in these members, as shown in Figs. 6 and 7.

A' felt oiling ring 59, of a size to have wiping engagement with the yinner wall of the air cylinder 32, is held in position by a plurality of wire clips 69 (see Figs. 6, 7 and 8) which are secured in position on the outer piston lring retaining plate 55 by screws 6|, threaded into the plate.

It will be noted in Figs. 6 and 8 that the inner piston ring retaining plate 51% is provided with air-annular projecting bead $2 of V-shaped cross section which penetrates the resilient material of the piston ring 53 to hold it against lateral displacement.

The main body portion of the resilient piston ring is of slightly less diameter than the internal diameter of the cylinder 42, as best shown in Fig. S. The piston ring, however, is provided with offset tapered, marginal flange 63 which projects outwardly into light wiping contact with the cylinder wall. rlhis arrangement insures an vair tight seal between the piston ring and the cylinder wall during an air actuation of the jack, and at the same time, due to the light wiping Contact of the flange 53 with the cylinder wall, facilitates the return of the jack to its normal position shown in Fig. l upon being` released from an actuated condition.

Anoiling wick @d is inserted through an opening in the top of the piston rod oil reservoir 52, a short length of tubing 55 being welded to surround the opening through which the wick is insertcd to avoid spilling of oil when the jack moves to'an operated condition. The upper end of the wick is placed in contact, as by inserting it beneath thefelt oil ring 59, and is held in position therein by means of one of the spring clips 60.

An oil ller plug 5l is threaded into a ller opening near the front or outer end of the hollow piston rod 52. The front, or outer end of the piston rod is closed, and is provided with a transversely mounted bushing 63 which extends laterally on each side of the piston rod to a point just within the sides of the tilting frame 2|, as shown in Fig. 10.

A piston rod connecting pin 69 is inserted in this elongated bushing, and passes through a pair of sliding assemblies 79 and 1|, for connecting rthe piston rod 52 to the tilting frame 2|, which are mounted to slide on the upper flanges of the sides of the tilting frame 2|, as best shown in Fig. l0. Each of these slide assemblies comprises a pair oi side plates 'i8 with inwardly turned lower ends connected together by a plate 35 welded between them. A pair of connecting links 12 and i3, of T section steel, have bushings 'M and 'l5 welded to the front ends thereof. These bushings pivotally receive the pin 99 therein. rlhe inner or rear ends of the links 'l2 and 73- also are pro-- vided with bushings il and "E8, and are pivoted on a rod 'i9 mounted transversely between the triangular side plates 33 and 34, as best shown in Figs. l, 2 and 9. As best seen in Figs. l and 2, the links 'l2 and i9 are downwardly bent between their ends so that the end portions of each link are disposed at substantially ano-btuse angle to each other, which enables the jack to be pushed under the chassis of a vehicle further than would be the case if the links were straight.

A Vpair of forwardly and downwardly directed ears and l (see Fig. 6) are provided one on each side of the `forward end of the piston. rod 52, and a locking pawl 82 is pivoted between them. The nose of the pawl extends downwardly and is adapted to engage teeth in a rack 83 which extends lengthwise centrally of the elevating frame 2|. The ends of the rack are welded to angle iron cross braces 84v and'5 (see Fig. 5) mounted transversely between the sides of the frame 2|.

A coil spring 8l is connected in tension between theforward end of the pawl and a screw 88 threaded into theY forward end of the piston rod. This spring tends to urge the nose of the pawl downwardly into engagement with the rack.` A pawl release rod $9 is connected to the upper end of the pawl, and extends rearwardly through an opening in the transverse rear bracing plate 35. The rod is provided with a rearwardly extending handle portion 99 by means of which the pawl may be moved to releasing positionv by an operator.

A pair of load engaging lifting plates 9| and 92 are welded one to each side of the forward end of the elevating frame 2|.. These plates are tilted upwardly and forwardly at a slight angle with'respect to the elevating frame 2|, as best shown in Figs. l-l inclusive. Each is pro-vided with a double arcuate contour on its upper edge for engagingautomo-bile members having normal surfaces for engaging by the jack, such for example as round or I beam axles, bumpers and the like.

Since many modern automobiles no longer are provided with the formerly conventional axle arrangements, an adapter 93 is provided, as best shown in Figs. 3, 4 and l2. This adapter comprises a transverse supporting rod 95 of strong, stress resisting, material withl one or more supporting members 93 adapted to be threaded thereon. Each of these supporting members comprises a strip 9i of steel having a `short endflange (Lv 98 turned up at one end thereof. A triangular portion il@ is welded to the side of the strip opposite to the end iiange 98, and has a bushing $99 welded therein of a size freely to receive the support rod 95:1 therein.

W ith the support member, or members, if more than one are employed, turned to the position shown in Fig. 3, the strips l'l are adapted to fit beneath areas on the underside of an automobile or other object to be raised by the jack. When the support members are turned to the inverted position as shown in Fig. 4, however, the points presented by the triangular plates 99 are adapted to enter holes punched, for example, in the centers of coil spring support plates, as found in some linee action structures and other structures which are not adapted to be supported by ordinary jack hoisting structures. The triangular shape oi these members tends to center them any such holes or between any adjacent straight surfaces, and to hold them against slipping from such position.

In operating the device, an air hose lill, which is connected to a suitable source of compressed air, which is available in most shops and garages, is connected to open into the cylinder 42 through an air valve 1&2. The hose preferably is connected to the valve H92 by means of a usual quickdisconnect coupling.

When thus prepared -for operation, the jack may be rolled into position with its front end extending beneath an automobile to be raised. The lifting plates 9i and E52 are brought substantially beneath the point at which it is desired to engage the automobile for lifting. If the automobile does not present suitable structure at such point, the adapter may be placed in position on the lifting plates 9| and 92, as shown in Fig. 3 or Fig. 4.

Assuming, however, that the automobile is to be engaged by its rear axle, as shown in Fig 2, after the jack has been moved into position, suficient air is admitted to the cylinder to force the piston 69 forwardly. This moves the piston rod 52 forwardly, and places the links l2 and 13 under tension. The slide assemblies 80 are forced slidably by this action along the upper flanges f the side members of the tilting frame 2|. This action tends to raise the front end of the tilting frame 2l pivotally about its pivotal connection 22 to the base frame 29.

After the initial engagement of the lack with the automobile has been checked by visual observation, the valve i532 is opened to admit air to the cylinder l2 to raise the automobile to a desired height, as shown in Fig. 2. After the automobile has been raised to the desired height, the valve 152 is closed, and the air may be released irom the cylinder, if desired, permitting the tilting frame 2i to settle down and bring the pawl t2 into locking engagement with a tooth of the rack 83. This prevents further retraction of the piston rod and holds the jack in elevated condition.

When it is desired to lower the jack, air again is admitted to the cylinder to elevate the tilting frame sufficiently to release the pawl from engagement with the rack, whereupon the pawl may be tilted to releasing position by pushing the release rod 89 forwardly. Thereafter the air may be released from the cylinder, as by disconnecting the hose lill and opening the valve |02, whereupon the weight of the car will rapidly force the piston to eject the air from the cylinder. The jack then may be removed from beneath CII the automobile, after which the weight of the tilting frame 2l and its associated parts will return the parts to the normal position illustrated in Fig. l.

While I have illustrated and described a preferred form of my invention, it will be apparent to those familiar with the art that many changes can be made without departing from the spirit of the invention. .lt is desired, therefore, not to limit the invention except as specically defined in the following claims.

I claim:

l.. A jack comprising a low, wheeled horizontal base having an upwardly offset inner end portion. an elongated hoisting frame pivotally connected at its inner end to the inner end of the base, said frame having parallel sides, load engaging means on the outer end of the hoisting frame, a slide assembly comprising slide members engageable with and slidable longitudinally along said respective sides and a cross bar extending directly between and secured at its ends to said respective slide members, a tension element pivotally connected at its inner end to the upper portion of said upwardly oiset base portion and extending downwardly and forwardly to said slide assembly, connection means pivotally connecting the extreme outer end of the tension element to the slide assembly, power means for moving the slide assembly longitudinally of the hoisting frame, and means for releasably locking the hoisting frame in position with its outer end elevated above the base; said latter means comprising a rack Xed to and disposed longitudinally of the hoisting frame and a rack engaging pawl pivotally carried by the slide assembly.

2. A jack comprising a low, wheeled horizontal base having an upwardly offset inner end portion, an elgonated hoisting frame pivotally connected at its inner end to the inner end of the base, said frame having parallel sides, load engaging means on the outer end of the hoisting frame, a slide member engaging and slidable longitudinally along each of said sides, a cross bar secured at its respective ends to the respective slide members, whereby to move therewith, a tension element pivotally connected at its inner end to the upper portion of the said upwardly offset base portion and extending downwardly and forwardly to said cross bar, connection means pivotally connecting the eXtreme outer end of the tension element to the cross bar, power means for moving the slide members longitudinally along the sides of the hoisting frame, and means for releasably locking the hoisting frame .in position with its outer end elevated relative to the base; said latter means comprising a rack fixed to and disposed longitudinally of the hoisting frame in position underlying the cross bar throughout the distance of movement of the latter, and a pawl pivotally mounted on said connection means in position to engage the rack.

JOHN F. HARRIS.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 1,900,528 Statz Mar. 7, 1933 2,239,250 Jackson Feb. 4, 1941 FOREIGN PATENTS Number Country Date 164,921 Great Britain June 23, 1921 

